Moto Droid Help

My phone has been kind of slow lately so I decided to restart it. When my phone started up, the Motorola Logo was aligned to the left side of the screen and then turned into a black screen. I pressed the power button again only to get a black screen with the bottom buttons lighting up. Also, it keeps "restarting" and just shows the Motorola logo over and over. Has this ever happened to anyone before?